Path to Glory, Path to Death : THE FRENCH FOREIGN LEGION: A Complete History of the Legendary Fighting Force, <i> By Douglas Porch (HarperCollins: $35; 768 pp.)</i>

‘Scum,” they were called; “assassins, thieves, deserters without scruple”; “ex-officers, ruined gentry, anarchists and freed convicts”; “dropouts and misfits.” “Rogues and rabble,” they were called, “the scrapings of humanity”--and this by their comrades.

Those who faced them on the battlefield had less to say; by and large, they were dead.

These were the rough, tough, preternaturally savage fighters of the French Foreign Legion. These were men at the end of their tether who found a home among their fellow outcasts--and found glory, too, more than enough to go around. And graves.

They were--and are--the hired guns of France, a country that makes up in chutzpah what it sometimes lacks in courage. A mutiny in Madagascar? Send in the Legion. Insurrection in Indochina? No sweat.

Nor can anyone accuse France of still fieldings mercenaries to fight its battles. “They can’t be mercenaries,” say the French with exquisite Gallic logic: “We don’t pay them enough.”

They are foreigners, though, now as then. That’s how the Legion started, back in 1831, created in response to “a short-term refugee crisis.” The French always have had this problem: As the self-proclaimed “cradle of liberty” (13 years after our revolution, but who’s counting?), the country attracts refugees from less enlightened regimes. At the same time, the French don’t like foreigners. Et voila!--the Legion, whose “meager patrimony,” writes Douglas Porch, has been “the right to die for France in the wastes of its empire.”

Author Porch has a problem too. The world at large has long been seduced by the romanticism of a regiment of lost souls; the legionnaire himself has been glorified as half-man, half-myth. And Porch, even after painstaking research, often can’t tell one from the other.

Porch has bunged into 700-plus pages every shard of information he could unearth. Doubtless he knows more about the Foreign Legion than anyone else does. His, then, should be the definitive history. But it’s not.

The author waffles, along with the rest of us. On the one hand, the Legion is “a vehicle of salvation”; on the other “an instrument of exploitation.” Porch is torn, as well, among “admiration, horror and ambivalence.”

Nevertheless, he lays it all out, from the Legion’s formation in 1831 to 1961--when, one hallucinogenic night, Premier Michel Debre took to radio and TV to ask all of Paris to drive out to Orly airport to “persuade” invading Legion paratroops to lay down their arms. (They never came.)

With the book dense in detail, it’s perhaps best to skim through overly meticulous accounts of obscure skirmishes and let the Legion lore wash over you. True or false? Who cares?

Read about the epic brawls in grungy bars where wine was not sold by the glass but by the hour . Read about the Bordels Militaires Controles , mobile whorehouses that followed the troops; about the barracks pranks, the time a group of Spanish legionnaires invited an unpopular German to sup with them--from a soup kettle into which they’d dunked a severed Arab head.

Read about the “incorrigible duelists,” one of whom was cashiered not for dueling, not for losing (he won), but for hesitating to impale his opponent at the moment de verite; about the incorrigible patriot who got 30 days’ KP for shouting “Vive la France!” in the heat of battle; about the incorrigible drunk in Tonkin whose punishment was to be tied to a tree next to a water hole frequented by a tiger.

Read about a deserter who lured his old outfit into ambush, then carved name and date into the chest of his former commander; about a barracks game called coucou that makes Russian roulette look like ringalevio; about a crusty trooper who had an obscenity tattooed on the palm of his right hand, the one he saluted with.

And the battles: in Mexico (to prop up Emperor Maximilian), where faire Camerone --to do a Cameron (battle)--became a permanent part of the Legion language, meaning, quite literally, to fight to the last man. In Spain and Syria, where the most furious clashes by far were those between the Legion and units of Legion deserters now fighting for the enemy.

In Norway, where Legion-laden whaleboats were towed to shore to fight the occupying Nazis (and where, in the best tradition, the visitors paused to loot the town of Bjerkvik. In Dahomey, where Amazons--Amazons!--guarding their king gave as good as they got. And in Vietnam, a relative picnic compared with the Legion headquarters in Algeria, where troops in training marched until boots filled with blood, and took waterless desert dinners of dried rice and macaroni.

And who were these men for whom hardship was honor and surrender a sin? Anyone and everyone. There were defrocked priests and dishonored officers (one grizzled Russian private, asked his background by his commander, replied: “I was a colonel, colonel”). To be sure, there was a sprinkle of disenchanted lovers, pure adventurers, Rhodes scholars, black-sheep aristocrats, even Cole Porter (!). But in the main they were “statistics of misfortune,” men for whom the Legion was a last chance, no questions asked, and who “in heroic death actually redeemed their wasted lives.”

They deserted by the thousands, but as a rite of passage, a personal statement, a “performing art”; most returned, reenlisting under another false name.

And they fought. Oh, did they fight! For whom or for what? Not for God, or country, not for an ideal. They fought for the Legion, “fought to the last man to defend the regimental standard,” because for most, the Legion was the only entity to give them half a chance.

How did they fight, this polyglot platoon who could barely understand orders? “Always remember,” said one drill sergeant, “in the Legion we don’t fight like the knights of the Middle Ages. We fight as dirty as possible. The enemy doesn’t like that, but then, he’s the enemy and we don’t have to be particularly nice to him.”

As noted, Porch’s book, if anything, is too comprehensive. His narrative can be repetitious, muddled, contradictory. But the sad, and paradoxically noble, calling of the French Foreign Legion shines through.

“The Legion was brilliant at two things,” said Englishman Henry Ainslie, quoted by Porch: “killing and dying well, both of which they did frequently and with eclat.”

“It made it well worth the risk of death,” said Blaise Cendrars, ex-legionnaire turned author, “to meet these damned souls, who smelled of the galleys and who were covered with tattoos. None of them ever let us down. . . . The profession of a man of war is an abominable thing, and leaves scars, like poetry. You have it or you don’t.”

The Foreign Legion had it.